This invention relates to an ink fountain apparatus for supplying ink from an ink reservoir to a rotating cylinder of a printing press, and more particularly, to a novel ink fountain apparatus in which an ink fountain is provided beneath the rotating cylinder for applying ink to the cylinder and in which a continuous flow of ink is maintained from the ink fountain into a drain chamber of an end cap located at the end of the cylinder.
Although the invention may have a more general application, it is particularly applicable to flexographic printing presses which embody impression, plate and anilox cylinders and in which ink is supplied to the anilox cylinder by an ink fountain located beneath the anilox cylinder and interposed between two doctor blades which wipe ink from the cylinder. In conventional printing presses of this type, ink seals are provided at both ends of the ink fountain to contain the ink.
The ink sealing arrangements generally used for printing presses of this type have included 1) seals which contact the outer surface of the cylinder near the ends, and 2) seals which encase the anilox cylinder. The former arrangement generates heat, causing ink drying in areas which require cleaning. In the latter arrangement, due to the tendency of the anilox cylinder to throw ink, the excess ink may either dry or leak from the fountain.
Another problem of ink fountains of this type is that the ink pressure that builds up within the ink fountain affects the wipe of the ink metering doctor blade. Depending upon such factors as blade support, flow of ink and speed of the press, the fountain pressure can vary and change the ink meter of the blade in a manner which is beyond the control of the operator.
Another problem encountered in ink fountain apparatus of printing presses of this type is the phenomenon called "burping", that is, vibration of the ink metering doctor blade in such a manner as to allow an excessive quantity of ink to pass between the anilox cylinder and the doctor blade, allowing the ink film to be much thicker and causing printing problems.